Portable percussive tool



Feb. 17, 1931. A. H. COLLINS PORTABLE PERCUSS IVE TOOL 2 Sheets-Sheet 1 Filed April 5. 1928 s R m m. m

H m w W A A TTORNEY Feb. 17, 1931. COLLINS 1,792,893

PORTABLE PERCUSS IVE TOOL Filed Apri l .3, 1928 2 Sheets-Sheet 2 o v a 2? 7 /9 a my a? f' /7 /0 22 -Z5 25 q i, 1 i 7 5 WAY #6 INVE'N TOR ATTORNE Y Patented Feb. 17, 1931 UNHTED STATES PATENT OFFICE ANTHONY H. COLLINS, OF BRONXVILLE, NEW YORK, ASSIGNOR TO CHICAGO PNEU- MA'IIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY PORTABLE PERCUSSIVE TOOL Application filed April 3, 1928. Serial No. 266,964.

This invention relates to portable power operated percussive tools adapted to be manuall-y supported and directed to the work. It has practical application to tools for hand drilling and demolition work generally.

One object of the invention is to relieve the operator so far as possible of the shock and reaction of the tool when in operation. Another object is to provide a resilient support for the percussive motor of such a tool so as to protect it from the injurious efiects of vibration. Another object is to permit limited movement of the percussive motor but to retain the working tool in place by means secured to a fixed portion of the tool. Other objects will be'apparent from the detailed description which follows:

In order to illustrate the invention concrete embodiments thereof are shown in the accompanying drawings in which:

Fig. 1 is a vertical sectional'view through the supporting cylinder and retainer and showing a portion of the percussive motor also in section;

Fig. 2 is a view similar to Fig. 1 but showing the percussive motor in running position; and

Fig. 8 is a view similar to Fig. 1 showing a modification.

The invention comprises suitable means for manually supporting a percussive motor so that the motor has a limited range of movement, which movement is cushioned in both directions, with the result that the operator is relieved of the shocks, vibration and recoil incident to the operation of the motor. As shown in all of the figures of the drawings the supporting means comprise a cylinder 4 carrying one or more handles 5, the cylinder having an elongate chamber la wlthm which the percussive motor A is movably mounted. While handles 5 may be secured directly to or formed integral with cylinder 5, in the present instance they are provided on a back- 0 head 6 secured to the cylinder in any suitable manner as by bolts (not shown). Percussive motor A is herein disclosed as of the fluid pressure type and the baclrhead 6 provides for a motive fluid connection at 7 under control of a throttle valve 8 of any desired or conventional form, which is arranged to be controlled by a lever 9 positioned conveniently adjacent the handles 5. The opening of throttle valve 8 delivers pressure fluid directly into the rearward end of the chamber 4a.

Percussive motor A has a head portion 1.0 slidably fitting the interior of chamber 40!. and has a reduced portion or barrel 11 which extends beyond cylinder, suitable means bemg provided adjacent the outer end of the cylinder to support the barrel and to prevent leakage of motive fluid therearound. Such means preferably includes packing ring 12,

packing 13 and gland nut 14:. The motor herein shown has an axial piston chamber in which reciprocates a hammer piston 15, the movement of which is automatically controlled by a pressure thrown sleeve valve 16 disposed in a valve box 17 which has a lid 18 and a cap or head member 19, the latter having a series of ports 19a therethrough for admitting motive fluid from the rear portion of chamber 4a into the percussive motor. Head 10 supports packing members 20 and 21 at either end and has a reduced portion or chamber 22 therebetween into which the exhaust of percussive motor A is discharged.

A working tool, such as a demolition pick or drill bit B is received in the forward end of the piston chamber of motor A to receive the blows of piston 15, the steel or bit being preferably formed with a collar 12 to limit the extension of the shank within the motor. Suitable means are provided for retaining bit B in operative relation with motor A without interfering with the permissive movement of the latter within chamber 4a. The means herein disclosed consist of a coil spring retainer 23 threaded upon or otherwise secured to cylinder and reduced at its outer end to cooperate with bit collar 1) as shown, the retainer being of sufiicient length to permit free movement of motor A.

Cylinder 5 provides a bypass in the form of a passage 24 which opens into chamber 4a adjacent the opposite ends thereof. Cylinder 4 also has a series of exhaust ports 25 extending transversely through the walls thereof in a plane intermediate the ends of by-pass 24.

The operation of the tool is as follows: In

its normal or nonoperative position motor A extends well within chamber la, as indicated in Fig. 1, with exhaust ports 25 preferably out of register with exhaust chamber 22 of the motor. hen the operator actuates lever 9 to open throttle valve 8, the motive fluid which enters the rearward end of chamber 4a is effective first to move motor A as a unit forwardly (or handle cylinder rearwardly) thereby uncovering the upper port of the by-pass 24. Motive fluid then passes from the rearward portion of chamber 4a to the annular chamber formed'intermediate head 10 of the motor and packing ring 12 thereby providing a cushion of motive fluid on both sides of head 10 of the motor. This forward movement of the motor also brings exhaust chamber 22 of motor A into register with exhaust ports 25 in cylinder 4 so that motor A goes into operation and continues in opera tion so long as the throttle valve is held open and registry of the exhaust chamber with the exhaust ports is maintained. For effective work it is necessary for the operator to apply a certain amount of pressure to the tool and this pressure must be sufiicient to balance the tendency of percussive motor A to move too far forwardly in chamber 4a which results fromthe greater effective pressure area at the rear of motor 11 as compared with the annular chamber surrounding barrel 11 of the motor. Fig. 2 shows the tool in running position. On closing the throttle valve the weight of the tool or the pressure exerted by the operator, or both, force motor A back to the inoperative osition shown in Fig. 1.

In the modi ed form of the invention shown in Fig. 3, resilient means are provided in the small annular chamber surrounding barrel 11 within cylinder 4 to assist the air cushion therein to equalize or more nearly to equalize the effective pressures on opposite sides of head 10 of motor A. Such means preferably take the form of a coil spring 26 encircling barrel l1 and interposed between head 10 of motor A on the one hand andpacking ring 12 of cylinder l on the other. The provision of spring 26 insures the return of motor A to the non-running position shown in Figs. 1 and 3 and requires the application of less force on the part of the operator to maintain motor A in such position within cylinder 4 that exhaust ports 25 will register with exhaust chamber 22.

From the above it will be apparent that the present invention relieves the operator as well as the percussive motor of the shocks, vibration and recoil of a hand-supported power-operated percussive tool by resiliently supportingthe percussivemotor so that movement in either axial direction is yieldingly resisted, that the resiliency of the support for the motor is provided wholly or in part by air cushions, that the invention makes it possible to predetermine the amount of pressure which the operator must exert upon the tool to maintain the percussive motor in the position which will enable it to operate, and that the use of a steel or hit retainer which is of adequate length and which is secured to the fixed or handle portion of the tool enables the operator to loosen and withdraw the bit from the work regardless of the position of the percussive motor Within the fixed support for the same.

While preferred forms of the invention have been herein shown and described, it is to be understood that the invention is not limited to the specific details thereof but covers all changes, modifications and adaptations within the scope of the appended claims.

I claim as my invention:

1. A hand supported tool comprising a cylinder, handles on said cylinder, a percussive motor supported within said cylinder and extending therebeyond, said motor having a head slidably fitting the interior of said cylinder and a reduced portion extending therefrom, said cylinder providing a chamber rearwardly of said motor head and having hearing and packing means for the reduced portion of said motor and providing an annular chamber between said portion and said cylinder, means for admitting motive fluid to said annular chamber when said motor is in operation, and resilient means in said annular chamber interposed between said motor head and said cylinder means.

2. A hand supported tool comprising a cylinder providing an elongate chamber, handles on said cylinder, a percussive motor within said chamber and having a head slidably fitting the same and a reduced portion protruding therefrom, bearing and packing means adjacent the end of said cylinder for said reduced portion, means for admitting motive fluid to the rear end of said chamber, said cylinder having a by-pass from the rearward end of said chamber to the forward portion thereof to put motive fluid on the forward side of said head, said by-pass being closed by said head when in rearward position to insure a predetermined forward movement of said motor before said by-pass is opened.

3. A hand supported tool comprising a cylinder providing an elongate chamber, handles on said cylinder, a percussive motor within said chamber and having a head slidably fitting the same and a reduced portion protruding therefrom, bearing and packing means adjacent the end of said cylinder for said reduced portion, said cylinder having a by-pass from the rearward end of said chamher to the forward portion thereof to put motive fluid on both sides of said head when said motor is in operation, said cylinder also having exhaust ports therethrough intermediate the ends of said by-pass for the exhaust of said motor.

4. A hand supported tool comprising a cylinder providing an elongate chamber and having an open port intermediate the ends of said chamber, a fluid pressure percussive motor movable within said chamber, means ment of said motor in said chamber, and

means yieldingly urging said motor to a position to cut off said exhaust connection.

6. A hand supported tool comprising a cylinder providing an elongate chamber, hanlles on said cylinder, a percussive motor witha in said chamber and having a head slidably fitting the same and a reduced portion protruding therefrom, bearing and packing means adjacent the end of said cylinder for said reduced portion, said cylinder having a by-pass from the rearward end of said chamber to the forward portion thereof to put motive fluid on both sides of said head when said motor is in operation, said cylinder also having exhaust ports therethrough intermediate the ends of said by-pass for the exhaust of said motor, and a coil spring encircling said enclosed portion of said motor for yieldingly resisting outward movement of the same.

7 A hand supported tool comprising a cylinder providing an elongate chamber, a percussive motor arranged for limited sliding movement within said chamber and having a portion extending therebeyond, a working tool having a shank extending within said motor and a collar abutting the end of the same, and means on said cylinder extending beyond said motor for cooperation with said tool collar to maintain said working tool in operative relation with said motor.

8. A hand supported tool comprising a cylinder providing an elongate chamber, a percussive motor arranged for limited sliding movement within said chamber and having a portion extending therebeyond, a working tool or bit having its shank end extending within said motor to receive the blows of the latter and having a collar to engage the end of said motor, and a retainer secured to said cylinder for cooperation with the collar of said working tool without interfering with the movement of said motor within said cylinder chamber, and providing for movement of said working tool relative to said motor in any position of the latter within said cylinder.

Signed by me at New York, N. Y., this 31st day of March, 1928.

ANTHONY H. COLLINS. 

